Republican governor Scott Walker and Democratic challenger Tom Barrett began a final push Saturday to connect with voters in person before next week's historic recall election, appearing at farm breakfasts and restaurants and rallying campaign workers.

Walker is only the third US governor to face a recall. The drive to oust him was spurred by anger over his plan to effectively end most public workers' collective bargaining rights. Walker insisted he had to make the move to balance the state budget, but Democrats portrayed the measure as an attack on organized labor.

Polls show a tight race with only a handful of voters still undecided before Tuesday's election, and Walker and Barrett have been struggling to win them over for the past month. Both sides have called in outside support to encourage their base voters. Former President Bill Clinton appeared at a rally for Barrett on Friday in Milwaukee, while South Carolina governor Nikki Haley campaigned with Walker.

The race between Walker and Barrett, especially, has evolved into a national referendum on union power. Republicans across the country have rallied around the governor, helping him raise a jaw-dropping $31m in campaign cash, giving him a huge edge over Barrett.

The recall is a replay of the 2010 gubernatorial election in which Walker edged Barrett, and Republicans took control of both houses of the Wisconsin state legislature. Democrats hope a reverse result on Tuesday will show the party's fortunes are on the rebound after the 2010 election in which Republicans made big gains nationwide thanks to the tea party movement which advocates limited government and no tax increases.

The Wisconsin vote is being closely watched as a harbinger of the national election in November. A Walker victory would show that Republicans still have the edge in what has traditionally been a swing state, a sign that would bode well for Republican presidential nominee Mitt Romney. It would also encourage Republican governors who have taken similar steps to curb union rights, make deep cuts in spending, and avoid tax increases.

A Barrett victory would raise Democrats' hope that a strong grassroots effort fueled by thousands of volunteers can offset the Republicans' edge in campaign funds, particularly in congressional and state elections. Democrats also want to preserve union power, ensuring that a core constituency continues to exist, both in Wisconsin and nationwide.

Barrett released a new television ad Saturday, again calling on the governor to explain his role in an ongoing investigation of associates during Walker's tenure as Milwaukee county executive, but the candidates mostly used the day to meet voters.

Barrett, who serves as Milwaukee's mayor, spent the day on the other side of the state, starting with a dairy breakfast in Hillsdale, a town of 1,250 people about 90 miles east of Minneapolis. The rest of his schedule included stops at a cafe in St. Croix Falls, a pizza joint in Superior and the state Democratic party's office in Chippewa Falls.

"We're going to cover the whole state here in the next four days," Barrett said in a telephone interview. "I love it. This is the part that really gets your juices flowing. This is where I'm most confident, doing this."

Walker began his day before 7am, serving food at a dairy breakfast on a massive farm just outside Evansville, a city of 5,000 people about 25 miles south of Madison, the state capital. His agenda called for a stop at another dairy breakfast in Monroe county before visiting campaign field offices in Hudson, Wausau, Green Bay and Wauwatosa.

"I feel good," Walker said. "We're not taking anything for granted. We're working all the way up to 8pm on Tuesday."

The recall represents the latest chapter in a knockdown, no-holds barred political battle that has consumed the mid-western state.

The fight began in February 2011 when Walker introduced the measure restricting collective bargaining for unions representing public employees. Tens of thousands of people descended on the state Capitol to demonstrate against the plan and minority Democrats in the state Senate fled to Illinois in a futile attempt to block a vote.

Republicans who controlled the legislature pushed the plan through anyway. Democrats have been looking for payback ever since.

They ousted two Republican state senators in recalls last August and gathered enough signatures on recall petitions this winter to force Walker and four other Republican officeholders into Tuesday's elections.

• This article was corrected on 6 June 2012 because Hillsdale is east of Minneapolis, not west.